A thermal barrier coating (TBC) is applied to a gas turbine blade such as a stationary blade or a moving blade used in a gas turbine. To manufacture a gas turbine blade of high quality, a film thickness of the TBC needs to be controlled in a manufacturing process of the gas turbine blade.
PTL 1 discloses a technique relating to a coating thickness measuring gauge that measures a thickness of a non-conductive thin coating placed on a conductive substrate.